Battle for Mosul: IS 'using chemical weapons'
The first use of chemical agents in the battle for Mosul was recorded by the International Red Cross in March, when mortars were fired from IS-held areas injuring 12 civilians.
According to accounts the BBC has obtained from Mosul residents, there were a number of other incidents over the past few weeks, where IS militants are suspected of using crude chemical gas against residents and Iraqi troops.
Produced by: Nader Ibrahim, Dina Demrdash